LXR linux/arch/powerpc/platforms/powernv/opal-rtc.c

   1/*
   2 * PowerNV Real Time Clock.
   3 *
   4 * Copyright 2011 IBM Corp.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12
  13#include <linux/kernel.h>
  14#include <linux/time.h>
  15#include <linux/bcd.h>
  16#include <linux/rtc.h>
  17#include <linux/delay.h>
  18#include <linux/platform_device.h>
  19#include <linux/of_platform.h>
  20
  21#include <asm/opal.h>
  22#include <asm/firmware.h>
  23#include <asm/machdep.h>
  24
  25static void opal_to_tm(u32 y_m_d, u64 h_m_s_ms, struct rtc_time *tm)
  26{
  27        tm->tm_year     = ((bcd2bin(y_m_d >> 24) * 100) +
  28                           bcd2bin((y_m_d >> 16) & 0xff)) - 1900;
  29        tm->tm_mon      = bcd2bin((y_m_d >> 8) & 0xff) - 1;
  30        tm->tm_mday     = bcd2bin(y_m_d & 0xff);
  31        tm->tm_hour     = bcd2bin((h_m_s_ms >> 56) & 0xff);
  32        tm->tm_min      = bcd2bin((h_m_s_ms >> 48) & 0xff);
  33        tm->tm_sec      = bcd2bin((h_m_s_ms >> 40) & 0xff);
  34        tm->tm_wday     = -1;
  35}
  36
  37time64_t __init opal_get_boot_time(void)
  38{
  39        struct rtc_time tm;
  40        u32 y_m_d;
  41        u64 h_m_s_ms;
  42        __be32 __y_m_d;
  43        __be64 __h_m_s_ms;
  44        long rc = OPAL_BUSY;
  45
  46        if (!opal_check_token(OPAL_RTC_READ))
  47                return 0;
  48
  49        while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
  50                rc = opal_rtc_read(&__y_m_d, &__h_m_s_ms);
  51                if (rc == OPAL_BUSY_EVENT) {
  52                        mdelay(OPAL_BUSY_DELAY_MS);
  53                        opal_poll_events(NULL);
  54                } else if (rc == OPAL_BUSY) {
  55                        mdelay(OPAL_BUSY_DELAY_MS);
  56                }
  57        }
  58        if (rc != OPAL_SUCCESS)
  59                return 0;
  60
  61        y_m_d = be32_to_cpu(__y_m_d);
  62        h_m_s_ms = be64_to_cpu(__h_m_s_ms);
  63        opal_to_tm(y_m_d, h_m_s_ms, &tm);
  64        return rtc_tm_to_time64(&tm);
  65}
  66
  67static __init int opal_time_init(void)
  68{
  69        struct platform_device *pdev;
  70        struct device_node *rtc;
  71
  72        rtc = of_find_node_by_path("/ibm,opal/rtc");
  73        if (rtc) {
  74                pdev = of_platform_device_create(rtc, "opal-rtc", NULL);
  75                of_node_put(rtc);
  76        } else {
  77                if (opal_check_token(OPAL_RTC_READ) ||
  78                    opal_check_token(OPAL_READ_TPO))
  79                        pdev = platform_device_register_simple("opal-rtc", -1,
  80                                                               NULL, 0);
  81                else
  82                        return -ENODEV;
  83        }
  84
  85        return PTR_ERR_OR_ZERO(pdev);
  86}
  87machine_subsys_initcall(powernv, opal_time_init);
  88